Poison Creeper

[Crystalion]

If the merc AI might be problematic, would it be worthwhile to look into an A1 or A3 merc and rely on summonable (and hence, placeable) minions to do the group gathering before being shockwaved into oblivion?

Well, if you had the choice, a Fire Golem would be perfect (I've recently been reminded of how "attractive" the FG's Holy Fire Aura is, making him a magnet for monsters to clump up on).

Failing that, an Act 2 HF merc might be good (same idea). The wolves don't have the HPs to easily survive for gathering unless they're pumped and the Grizzly has that knockback effect, which doesn't help clumping. I suppose it is conceivable that using Ravens to blind them once they're on the mat might help. (This is similar to suggesting to a PJav build to make the runeword helm Nadir--NefTir--with 9 charges of slvl 13 Cloak of Shadows, 20 seconds duration unclipped by difficulty)

My Bermat experiment is clvl 30 now... I'm not real thrilled with Armageddon (targeting issues) compared to Hurricane. Still, Armageddon ramps up and fits with the shockbear/mat concept, whereas Hurricane can't be recast in bearform.